The present invention relates to a headrest arrangement for a vehicle seat comprising at least one backrest and a headrest device.
Vehicle seats often comprise headrests which are fastened to the upper end of a backrest. In this context, different fastening possibilities can be considered. For example, the headrest can be connected fixedly to the backrest but can also be height-adjustable and pivotable in order to be adapted to the anatomy of different vehicle passengers.
Conventional vehicle seats have the problem that the spacing between the back of the head of a vehicle passenger and the headrest can possibly be very large depending on the seating position of the vehicle passenger. This problem occurs especially, but not exclusively, in regard to vehicle seats where the incline of the backrest can be selected differently.
A large spacing between the back of the head and the headrest, however, is very dangerous for the vehicle passengers in the case of an accident, especially in the case of a rear impact. In the case of an impact, a very great relative acceleration between the headrest and the head of the vehicle passenger occurs which results in a very hard impact of the back of the head on the headrest. Severe head injuries can be the result.
A solution for preventing such a great spacing between the back of the head and the headrest is proposed in DE 298 08 831 U1. The vehicle seat described therein comprises a two-part backrest. An upper part of the backrest on which the headrest is fastened is rotatably embodied relative to the lower part of the backrest. In this connection, the upper part is forced by a spring into a forward rest position and is pivotable toward the back when the vehicle passenger rests against it. A disadvantage of this system is the high manufacturing expenditure. In order to be able to ensure a protection as effective as possible in the situation of accidents, not only the installation of a spring means but also of a shock absorber is required. Moreover, the construction described here is only suitable to a limited extent for the vehicle backseats. Finally, the movable construction of the backrest can be perceived as uncomfortable by some vehicle passengers.
It is therefore an object of the present invention to provide a headrest arrangement for a vehicle which reduces the injury risk for the neck area and back area of the neck of the vehicle passenger in an accident and is furthermore characterized by a simple configuration.
According to the invention, a headrest arrangement is provided for a vehicle seat comprising at least one backrest and a headrest device. A mechanical transmission device is provided for the transformation of a deformation of the backrest into a movement of the headrest device.
The invention resides substantially in that a mechanical transmission device transforms a deformation of the backrest into an oppositely oriented movement of the headrest device so that the headrest device is moved toward the back of the head of the vehicle passenger. The deformation of the backrest is effected by the inertia forces which the vehicle passenger exerts onto the backrest, for example, in the situation of a rear impact. Accordingly, this is a purely passive system which requires no active components. The advantage of a minimal service expenditure can therefore be realized together with a very high reliability of the system. Moreover, also with regard to manufacturing technological considerations, the seat and headrest arrangement according to the invention can be relatively easily manufactured because it requires only a few component groups.
An especially preferred configuration of the headrest arrangement can be realized when for forming the transmission device the backrest comprises a deformable support structure which is supported on a contact device in a bending-resistant transition area between the backrest and the headrest device. The support structure forms the mechanically stable part of the backrest and can be upholstered for improving the comfort of the seat. The support structure deforms when an accident occurs and, by means of the mechanical transmission device, the headrest device is moved. The support structure can be formed in any suitable way, for example, as a surface member or as a grate member and can be subsequently embedded in foam in a known manner with an upholstery material. A surface member configuration of the support structure can also be provided with holes so that embedding in foam can be realized more easily and more permanently.
It has been proven to be especially advantageous to form the support structure as a shell-like support shell. This makes it possible in an especially easy way to adapt the backrest to the shape of the anatomy of the back and to thus realize an especially comfortable vehicle seat. It is especially advantageous that with such a backrest the upholstery portions can be provided over the entire surface area of the backrest with substantially the same thickness which is very advantageous with respect to manufacturing technological aspects.
The headrest device can be connected by fastening means with the support structure so that known headrest devices can be employed for realizing the headrest arrangement.
An especially simple configuration results when at least one part of the headrest device is formed by a correspondingly shaped part of the support structure. Such a one-part, integral configuration allows an especially inexpensive production. A possibly required stiffening in the transition area between the support structure and the headrest device can be realized, for example, in that the material in the area of the headrest device has a greater cross-section or that in the transition area recesses are provided in which additional reinforcement elements can be inserted.
It is especially advantageous to provide a stop device which limits the deformability of the backrest. With such a stop device, the movement of the backrest can be limited to such an extent that, when an accident occurs, the upper body remains in a substantially vertical position in which the accelerations occurring during an impact present the most minimal injury risk for the vehicle passengers. At the same time such a stop device can also represent the contact device of the mechanical transmission device, which in cooperation with the support structure of the backrest, transforms the deformation of the backrest into a movement of the headrest device. For example, in the simplest case, the stop device can be comprised of a profile which is connected to the car body and on which, in the case of the headrest device being connected directly to the backrest, the transition area between the headrest and the backrest is supported. For example, a rearwardly oriented deformation of the backrest is then transformed in the simplest manner into a forward movement of the headrest device. However, other embodiment variants of the stop device are possible, for example, the use of a rotary joint.
In order to avoid an excessive deformation of the backrest with respect to the anatomy of the back, which could result in itself in injuries in the back area of the vehicle passenger, an especially preferred embodiment of the stop device is characterized in that it is of a cavity shape. Accordingly, the backrest, in its maximally deformed position, is also cavity-shaped so that the risk of injury is reduced. Such a cavity-shaped stop device can especially be substantially sheet-like. Since, generally, in any type of vehicle seat a structure is to be provided that is as stable and as sheet-like as possible and provides protection against loose parts which could fly forward during an accident, such a cavity-shaped stop device can be realized without great additional expenditure.
It is a further advantage when for the headrest arrangement the configuration of the support structure of the backrest, respectively, the materials for the backrest as well as for the support structure are selected such that the backrest acts as an energy-dissipating means. Accordingly, already during the deformation of the backrest when an accident occurs, a deceleration of the vehicle passengers can be achieved so that the maximum acceleration forces acting on the vehicle passenger are reduced. The vehicle seat acts thus as an additional crumple zone and is thus especially safe.
When the headrest arrangement is provided on a backseat, the backrest can be used at the same time for forming a divider between the passenger compartment and the trunk space.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.